Has she had a swallow study?
my neice has been scoped maybe 4 times she is only 6 now, but has EE (eosonophilic esophagitis) the scope helped her GI doctors diagnose her. there's not much to do but get either formula, or feeding tube as well as any kind of autoimmune meds that are appropriate. You do need a diagnosis to get insurance to cover the treatments that are suggested. It was really tough on her, and even harder for my sister. But it is in the past now and they have what they need to work on her every day health. Best of luck whatever you decide.
I can only think of adults top of mind but a friend just had it done Monday. A little sore throat afterwards. Meet and speak with the Anestheologist before surgery make sure you have confidence in that person.